The present disclosure concerns, according to a first aspect, a method for assessing passages by a vehicle through a tolling object. According to another aspect, the disclosure concerns a system for conducting said method.
Systems and methods for automatic controlling passages of objects, typically vehicles, into and/or out from certain geographic areas why possibly assigning them to distinct road segments, have been developed during the recent decades, and systems and methods based on Global Navigation Satellite Systems (GNSS) technology are prevailing.
Satellite based road tolling systems are rapidly growing in number due to their versatility and flexibility. It allows for an advanced time/distance/place concept where policy makers can adjust prices to best fit their objectives. A number of distinct tolling schemes may be applied based on a combination of segment based tolling where road usage cost is derived from use of road segments; cordon based tolling where there is a cost associated with travelling into (or out from) a zone; virtual gantry based tolling where there is a fee associated with crossing a virtual tolling point; and finally distance based tolling where the fee is derived from the distance driven. The tolling schemes can be divided into discrete schemes (segment, cordon zone, and gantry) and continuous scheme (distance). Non-repudiation of the tolling statement is a very important aspect of the toll system. This includes both proving that the toll statement is genuine and proving that the system correctly identifies vehicles travelling in and out of tolling zones.
Even if the average performance and availability of GNSS systems today are very good, there will still be situations where the tolling system may be mislead by erroneous position estimates from the GNSS system. In particular in geographical areas where parts of the sky are obstructed by natural or man-made objects this may be of great concern.
GNSS based tolling and the system model in FIG. 1 is described by international standards. Of most relevance to this disclosure is ISO 17573 Electronic Fee Collection—Systems architecture for vehicle-related tolling and ISO 12855 Electronic Fee Collection—Information exchange between service provision and toll charging. The European Union is working towards a common European interoperable system for tolling where road users have On Board Units (OBU) and a contract with one home toll operator enabling pan-European roaming where foreign toll charges are invoiced through the home toll operator. This is known as the EETS directive, Directive (2004/52/EC) of the European Parliament and of the Council of 29 Apr. 2004 on the interoperability of electronic road toll systems in the Community. Furthermore the European Commission Decision (2009/750/EC) of 6 Oct. 2009 on the definition of the European Electronic Toll Service and its technical elements puts this into effect.
A satellite based road tolling system comprises 3 main physical elements: 1) The satellites, 2) vehicles equipped with OBUs observing signals from the satellites, and 3) a so-called back office.
The most typical use of such systems is for tolling, where each vehicle owner pays a certain fee for use of the road. The reliable detection of zones, virtual gantries, and segments are important aspects of such tolling systems. In general there are three kinds of errors encountered with the use of such systems, one being a false registration of an event, the other being missed recognition of an event that actually occurred; the detection may erroneously be attributed to a wrong location or a wrong time; additionally the travelled distance may be calculated wrongly. All errors may result in lower user confidence in the system and increased operational costs.
The use of particle filters for estimation in general, and for positioning in particular, is known from the scientific literature. Two papers in particular give a good overview of the methods: “An Overview of Existing Methods and Recent Advances in Sequential Monte Carlo” (Olivier Cappé Simon J. Godsill, and Eric Moulines, Proceedings of the IEEE, Volume 95, Issue 5, 2007), and “Particle Filters for Positioning, Navigation and Tracking” (Fredrik Gustafsson, Fredrik Gunnarsson, Niclas Bergman, Urban Forssell, Jonas Jansson, Rickard Karlsson, Per-Johan Nordlund, IEEE Transactions on Signal Processing, Special issue on Monte Carlo methods for statistical signal processing, Issue 2, February 2002).
EP 1 332 336 B1 concerns a method and a system for positioning of a moveable object. More specifically, this publication relates to a map-aided positioning system wherein map information and relative position information is combined to estimate an absolute position indication by calculating a position estimate by recursively estimating in a non-linear filtering algorithm the conditional probability density for the position.
US20090132164 A1 teaches a reinforcement learning technique for online tuning of integration filters of navigation systems needing a priori tuning parameters, such as Kalman Filters and the like. The method includes receiving GNSS measurements from the GNSS unit of the navigation system; and IMU measurements from IMU of the navigation system. The method further includes providing a priori tuning parameters to tune the integration filter of the navigation system. The method further includes processing the GNSS and IMU measurements using the tuned integration filter to compute a position estimate and updating the a priori turning parameters based on the computer position estimate.
US20130265191 describes a method of determining a geographic position of a user terminal including a receiver of signals of a global navigation satellite system, the method including the user terminal: performing pseudo-range measurements related to a plurality of signals received from transmitters of the global navigation satellite system; calculating a first estimated position thereof by a weighted least squares method; calculating post-fit residuals for the first estimated position; comparing the calculated post-fit residuals to a first threshold and: in case the first threshold is exceeded, calculating a second estimated position using a Monte-Carlo method, otherwise retaining the first estimated position as the geographic position of the mobile communications terminal.
U.S. Pat. No. 7,324,017B2 concerns a process for determining travel through at least one toll road section by at least one vehicle by means of a position determination system which is set up to determine the current position of the at least one vehicle, whereby positions of the at least one vehicle are compared with the position of at least one reference point characteristic for an entrance to a toll road section, whereby the orientation of the vehicle is determined within a specifiable region about the entrance, whereby it is determined whether the orientation determined agrees within a specifiable tolerance range with the orientation characteristic of entry onto the toll road section.
EP2230644A1 describes a method which involves maintaining global positioning systems of vehicles in standby. Positioning functions of the global positioning systems are stimulated at the proximity of geographical positioning points e.g. taxation points, where the stimulation of the positioning function of each global positioning system is calculated from an origin positioning instant, near geographical positioning point and maximum speed of the vehicles.
In spite of the teachings mentioned above there is still a need for improved methods and systems for detection of objects, such as vehicles, passing into and out from a geographical zone, crossing virtual gantries, and driving on certain segments of the road network, providing improved reliability and reduced risk of false one crossing assessments.